This invention relates to portable breath alcohol detectors of the type sold under the trademark ALCO-SENSOR by Intoximeters, Inc., of St. Louis, Mo., which use a standard tubular mouthpiece of a type described generally in Jones et al. U.S. Pat. No. 3,940,251, a straight cylinder with a small hole mid-way of its length, thru which projects a stub tube mounted on an upper wall of the housing of the detector. Heretofore, a subject whose breath is to be tested blows through the tube, and either after a predetermined period or when the operator thinks that the subject is exhaling deep lung breath, the operator causes a sample to be taken of the passing breath, the sample being sucked through the stub tube, in a metered amount, into a fuel cell that may be of the type described in Wolf U.S. Pat. No. 4,487,055.
If the sampling time is determined by the Police Officer, it is often under somewhat difficult circumstances. It may be dark, and the subject is likely to be uncooperative. Accordingly, the Officer is not able easily to tell if the subject has stopped blowing momentarily or has inhaled, either of which will jeopardize the proper results of the test.
Audible signals in connection with breath testing equipment have been described heretofore. However, those devices had a disadvantage of being liable to sound when the subject inhales, and of trapping breath alcohol which is brought back into the system when the subject inhales.
One of the objects of this invention is to provide an audible signal indicating that the subject is blowing into the mouthpiece, that stops sounding when the subject either stops blowing or inhales, and at the same time does not permit residual alcohol from a previous test to be introduced to the mouthpiece upon inhalation by the subject.
Another object is to provide such a device that creates no substantial impediment to the flow of breath nor introduces ambient air into the breath stream.
Yet another object is to provide such a device that is simple and that automatically assures the proper orientation of the mouthpiece.
Other objects will become apparent to those skilled in the art in the light of the following description and accompanying drawing.